Infodoc : Sciences, Techniques et Culture

South America’s tropical lowland forests cover world’s greatest amount of terrestrial biodiversity (Hans ter Steege et al. 2006) with an estimated number of 16000 tree species(H. ter Steege et al. 2013). Such great diversity is the origin of challenging and empirical explanation of vegetation patterns (Tuomisto 2003). It is already known that biodiversity is not equally spatially distributed: the Guiana’s shield is characterized by lower diversity than forests of western Amazonia (Hans ter Steege et al. 2000). Still, more than 1300 tree species have actually been recorded in French Guiana (Freycon et al. 2003).
In forests, habitats diversity considerably supports regional species richness (Hans ter Steege et al. 2000) and differs according to biotic – floristic composition – and ab[...]

South America’s tropical lowland forests cover world’s greatest amount of terrestrial biodiversity (Hans ter Steege et al. 2006) with an estimated number of 16000 tree species(H. ter Steege et al. 2013). Such great diversity is the origin of challenging and empirical explanation of vegetation patterns (Tuomisto 2003). It is already known that biodiversity is not equally spatially distributed: the Guiana’s shield is characterized by lower diversity than forests of western Amazonia (Hans ter Steege et al. 2000). Still, more than 1300 tree species have actually been recorded in French Guiana (Freycon et al. 2003).
In forests, habitats diversity considerably supports regional species richness (Hans ter Steege et al. 2000) and differs according to biotic – floristic composition – and abiotic factors – soil composition and climate (Tuomisto 2003). In French Guiana, soils are characterized by low fertility – low concentration in nutrients, resulting from high leaching associated with high annual rainfall – between 2000 and 5000 mm per year (Hans ter Steege et al. 2000). This specific association between soil and climate leads to binding effects for plants such as low cationexchange capacity,low pH,high aluminum proportion(Freycon et al. 2003). Freycon et al.(2003)described different habitats – white sand forests, terra firme forests, seasonally flooded forests – according to soil, texture and fertility varying with parent material. Those forests are also known to be distinct regarding floristic composition and dynamic (Tuomisto 2003; Koschorreck et Darwich 2003; Ferry et al. 2010).